If your device is not charging when you use the USB4 C-to-C Cable (ST-U4C80M and ST-U4C25M), the cause is usually the power adapter, the port, or a connector that is not fully seated. The USB4 C-to-C Cable supports up to 100W of USB Power Delivery (PD), and both the power adapter and the device being charged have to support the wattage you expect. The USB4 C-to-C Cable needs no drivers or software, so work through the steps below in order.

Steps to fix charging with the USB4 C-to-C Cable

1. Unplug both ends of the USB4 C-to-C Cable and plug them back in firmly. USB-C connectors are reversible, but a loose connection will stop charging.
2. Check the wattage of your power adapter. The USB4 C-to-C Cable supports up to 100W of USB Power Delivery (PD), so a lower rated adapter will charge more slowly or not at all.
3. Confirm the device you are charging supports the wattage you expect. The cable cannot exceed what either the power adapter or the device supports.
4. Try a different USB-C port on the power adapter and on your computer to rule out a faulty port.
5. Charge a different device with the same adapter and the USB4 C-to-C Cable. If the second device charges, the issue is with the first device rather than the cable.
6. Inspect both USB-C connectors and the braided cable body for debris or visible damage.
7. Test the same adapter and device with a different USB-C charging cable. If charging works with the other cable, the USB4 C-to-C Cable is the part at fault.
8. Install any pending operating system updates, then reconnect the USB4 C-to-C Cable.